Return-Path: Received: from rly-dc02.mx.aol.com (rly-dc02.mail.aol.com [172.19.136.31]) by air-dc05.mail.aol.com (v121_r4.4) with ESMTP id MAILINDC053-b0649398e8772; Fri, 05 Dec 2008 15:27:09 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dc02.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINDC022-b0649398e8772; Fri, 05 Dec 2008 15:26:49 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1L8hFv-0006QL-17 for rs_out_1@blacksheep.org; Fri, 05 Dec 2008 20:26:31 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1L8hFu-0006QC-Ek for rsgb_lf_group@blacksheep.org; Fri, 05 Dec 2008 20:26:30 +0000 Received: from pne-smtpout2-sn1.fre.skanova.net ([81.228.11.159]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1L8hFt-00049C-RW for rsgb_lf_group@blacksheep.org; Fri, 05 Dec 2008 20:26:30 +0000 Received: from [127.0.0.1] (62.20.250.99) by pne-smtpout2-sn1.fre.skanova.net (7.3.129) (authenticated as u33233109) id 4843FAEB02C4D554 for rsgb_lf_group@blacksheep.org; Fri, 5 Dec 2008 21:26:24 +0100 Message-ID: <49398E6F.4010600@telia.com> Date: Fri, 05 Dec 2008 21:26:23 +0100 From: "Johan H. Bodin" User-Agent: Thunderbird 2.0.0.18 (Windows/20081105) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: In-Reply-To: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: E field active antennas Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Andy, I don't think the helical shape of the element will have any significant impact on performance unless the frequency is approaching half wave resonance of the helix itself (by half-wave resonance I mean hi-z at the ends, virtually non-terminated, with a current maximum at the center). I'd guess that the helix will equal a tube of the same physical length but with slightly less capacitance, perhaps moving the LF corner a little bit up (depending on amplifier input R of course). 73 Johan SM6LKM --- Andy Talbot wrote: > but then started wondering if doing that would make any > difference to performance.